Wash. Rev. Code § 26.16.100
A spouse or domestic partner having an interest in real estate, by virtue of the marriage relation or state registered domestic partnership, the legal title of record to which real estate is or shall be held by the other, may protect such interest from sale or disposition by the other spouse or other domestic partner, as the case may be, in whose name the legal title is held, by causing to be filed and recorded in the auditor's office of the county in which such real estate is situated an instrument in writing setting forth that the person filing such instrument is the spouse or domestic partner, as the case may be, of the person holding the legal title to the real estate in question, describing such real estate and the claimant's interest therein; and when thus presented for record such instrument shall be filed and recorded by the auditor of the county in which such real estate is situated, in the same manner and with like effect as regards notice to all the world, as deeds of real estate are filed and recorded. And if either spouse or either domestic partner fails to cause such an instrument to be filed in the auditor's office in the county in which real estate is situated, the legal title to which is held by the other, within a period of ninety days from the date when such legal title has been made a matter of record, any actual bona fide purchaser of such real estate from the person in whose name the legal title stands of record, receiving a deed of such real estate from the person thus holding the legal title, shall be deemed and held to have received the full legal and equitable title to such real estate free and clear of all claim of the other spouse or other domestic partner.
RCW 26.16.100
SLC-RO-16.
Part headings not law-Severability-2008 c 6: See RCW 26.60.900 and 26.60.901.
Recording of real property by county auditor: Chapters 65.04 and 65.08 RCW.